Before the movie Man of Steel has been released, it was already announced by Director Zach Snyder there would be a cameo for the late Christopher Reeve, who have portrayed several Superman movies. Though Snyder didn’t tell to which part of the movie Reeve would be seen, I think its kinda Easter Egg trivia from MOS and to pay tribute as well to the late CR.
I don’t know to others but I kinda noticed the part when the Earth has been evaded by the Kryptonian aliens and Superman has to get his flight back to save the world, while the camera is on a little bit slow mo mode and focuses Henry Cavill’s face, the face of Christopher Reeve has been imposed to his face and I was like, “he looks like Christopher Reeve!”. The change or the imposition of his face to Cavill’s is quite obvious if you really gonna realize it. After a few days, there are enormous statements from audiences who watched the movie and yes, they also saw Reeve’s face in that moment. So it’s real. And it was confirmed by Director Snyder as well as other critics. I have to look at it again so I’ve searched the web for documentation (hahaha). So here it is from Man of Steel moviegoer who also happened to notice the obvious Easter Egg from MOS production team. I bet a lot noticed it. If you’re not sure of what you saw, here’s a clip from that scene to look back to. Aren't they look alike?
(PS: This video is not mine)